Flaw detection apparatus using two detectors to assure unbalance in a comparison circuit

Claim 1

A FLAW DETECTION SYSTEM COMPRISING: A SOURCE OF PENETRATING RAY ENERGY; MEANS FOR SUPPORTING AN OBJECT TO BE INSPECTED FOR FLAWS; TWO PENETRATING RAY DETECTORS, SAID DETECTORS BEING DISPOSED RELATIVE TO SAID SOURCE AND TO SAID SUPPORT MEANS SUCH THAT SAID INSPECTION OBJECT WHEN MOUNTED ON SAID SUPPORT MEANS IN INTERPOSED BETWEEN SAID SOURCE AND SAID DETECTORS, WHEREBY EACH OF SAID DETECTORS HAS AN EFFECTIVE FIELD OF VIEW ON AND THROUGH SAID INSPECTION OBJECT; SAID DETECTORS BEING SPACED FROM EACH OTHER ALONG AN IMAGINARY LINE HEREINAFTER REFERRED TO AS THE TWO-DETECTOR LINE; MEANS FOR PROVIDING RELATIVE MOTION BETWEEN SID INSPECTION OBJECT AND SAID DETECTORS HAVING A TRANSLATIONAL COMPONENT OF MOTION PARALLEL TO SAID TWO-DELECTOR LINE AND A CYCLICAL COMPONENT OF MOTION IN A PLANE PERPENDICULAR TO SAID TWODETECTOR LINE; SAID RELATIVE MOTION PROVIDING MEANS INCLUDING MEANS FOR CONSTRAINING SAID TRANSLATIONAL COMPONENT OF MOTION TO A MAGNITUDE EQUAL TO OR LESS THAN TWICE THE SUM OF THE DISTANCE BETWEEN THE FIELDS OF VIEW OF SAID TWO DETECTORS IN THE DIRECTION OF SAID TWO-DECTECTOR LINE AND THE LENGTH OF SAID FIELD OF VIEW IN THE DIRECTION PARALLEL TO SAID TWO-DECTECTOR LINE, DURING EACH COMPLETE CYCLE OF SAID CYCLICAL COMPONENT OF MOTION; WHEREBY NO FLAW IN SAID INSPECTION OBJECT CAN AT ANY POINT IN THE TIME SIMULTANEOUSLY INTERCEPT THE FIELDS OF VIEW OF BOTH DETECTORS WITHOUT INTERCEPTING THE FIELD OF VIEW OF SOLELY ONE OF SAID DETECTORS AT SOME OTHER POINT IN TIME.